Calculate subnets, IP ranges, CIDR notation, and network details
Enter an IP address and click Calculate
Or select a quick preset above
About SubnettingSubnetting divides a network into smaller segments. The CIDR notation (like /24) indicates how many bits are used for the network portion.
CIDR Reference| CIDR | Mask | Hosts |
|---|---|---|
| /24 | 255.255.255.0 | 254 |
| /25 | 255.255.255.128 | 126 |
| /26 | 255.255.255.192 | 62 |
| /27 | 255.255.255.224 | 30 |
| /28 | 255.255.255.240 | 14 |
| /29 | 255.255.255.248 | 6 |
| /30 | 255.255.255.252 | 2 |
Private IP RangesClass A: 10.0.0.0 — 10.255.255.255
Class B: 172.16.0.0 — 172.31.255.255
Class C: 192.168.0.0 — 192.168.255.255
What is Subnet Calculator?Subnet Calculator is a free online tool for network administrators and engineers to calculate IP subnet details. Enter an IP address with CIDR notation or subnet mask to get network address, broadcast address, usable host range, and total number of hosts. Essential for network planning and IP address management.
Our calculator supports IPv4 subnetting and provides detailed breakdowns of network classes, wildcard masks, and binary representations for educational purposes.
Key Features
CIDR NotationCalculate subnets using CIDR notation (/24, /16, etc.) or traditional subnet masks.
Host RangeGet the first and last usable IP addresses in any subnet instantly.
Binary ViewSee binary representations to understand how subnetting works.
Network PlanningPlan network segmentation with accurate host counts and address ranges.
Frequently Asked QuestionsCIDR (Classless Inter-Domain Routing) notation represents IP addresses with their subnet mask as a suffix. For example, 192.168.1.0/24 means the first 24 bits are the network portion, leaving 8 bits for hosts (254 usable addresses).
A /24 network has 256 total addresses (2^8), but only 254 are usable for hosts. The network address and broadcast address are reserved, leaving 254 addresses for devices.
A subnet mask divides an IP address into network and host portions. Common masks include 255.255.255.0 (/24) for 254 hosts and 255.255.0.0 (/16) for 65,534 hosts.
Everything this tool does, available as a simple REST endpoint with JSON responses — perfect for scripts, monitoring and integrations. Free tier: 100 requests/month, no card required.
curl -H "X-API-Key: tn_your_api_key" \
"https://tools-ninja.com/api/v1/subnet?ip=192.168.1.0&cidr=24"